1. Field
One embodiment of the invention relates to an information processing apparatus in which video decoding processing for decoding a compressed and encoded video stream is achieved by software, and a video decoding method thereof.
2. Description of the Related Art
As standard technologies for encoding a video stream, H.261 and H.263 of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), Moving Picture Experts Group (MPEG)-1, MPEG-2, and MPEG-4 of the International Organization for Standardization (ISO), and the like, have been developed. As a next-generation video encoding method in which the technologies such as H.261 to H.263, MPEG-1 to MPEG-4, and the like have been succeeded, and further developed, there is the H.264 which has been standardized by the ISO and the ITU jointly (refer to ITU-T Recommendation H.264 (2003), “Advanced Video Coding for generic audiovisual services”|ISO/IEC 14496-10: 2003, “Information technology, Coding of audio-visual objects—Part 10: Advanced video coding”, and H.264/AVC textbook (Impress Communications Corporation)).
However, while on the other hand the H.264 achieves a high compression ratio, it poses a serious problem because it is required a high computing processing capability when reproducing a video image with a high resolution, especially, like an HD-DVD.
On the other hand, personal computers (PCs) having the same AV functions as those of audio-video (AV) equipment such as digital versatile disc (DVD) players and TV devices have been developed. In such a personal computer, a software decoder which decodes a compressed and encoded video stream by software is used. By the use of a software decoder, it is possible to decode a compressed and encoded video stream by a processor (CPU) without dedicated hardware being provided thereto.
However, in an information processing apparatus such as the foregoing personal computer, in accomplishing video decoding processing according to the standardization specifications, etc., based on the H.264, in a video decoding apparatus with such standardization specifications based on the H.264, compensating movements of inter predictions accounting to the whole of decoding processing being large in quantity, there is a possibility that such a disadvantage occurs that decoding processing in real time cannot be made in time, frames are missed, and movements of objects are extremely become slow, if the load on the whole of the decoding apparatus is heavy. Specifically, in an information processing apparatus driven by a battery, such as a notebook personal computer, increasing a load in a battery driven mode consumes a large volume of electric power and shortens a driving time extremely.